[SOLVED] Configure GPIO Wakup from Suspend

Hardware: Custom board based on at91sam9263ek


I'd like to be able to wakeup from standby using a GPIO pin.

I can currently enter standby mode and wake up by using the RTC:

#Standby for 60 seconds, then wake up
echo "" > /sys/class/rtc/rtc0/wakealarm
echo "+60" > /sys/class/rtc/rtc0/wakealarm
echo standby > /sys/power/state

How can I configure a GPIO Wakeup event from standby state? Is there a way to do this from user space, or does it need to be written into a driver?

Thanks,
Nate

I would not advise trying to do this in user space. Do it the right way to begin with, as a kernel module/component.

Check out these bits of documentation in the Linux source tree if you haven't already:

Documentation/power/devices.txt
Documentation/gpio.txt

Essentially, you need to:

- Register the input gpio
- Register an ISR for that GPIO via gpio_to_irq() and request_irq().
- Build out the power management operations as discussed in the above documentation.
- Arrange for yoru power management hooks to be called from the interrupt service routine

jhwilliams - thanks for the reply.

It sounds like I'm already halfway there.

I have written a touchscreen driver that has an irq generated from a GPIO. Here's a few cutouts:

#define TOUCH_IRQ_PINAT91_PIN_PB10 gpio_request(TOUCH_IRQ_PIN, "PB10"); gpio_direction_input(TOUCH_IRQ_PIN); request_irq(TOUCH_IRQ_PIN, read_interrupt, IRQF_SHARED,"touchScreenIRQ", INT_ID); DECLARE_WORK( mywork, my_workqueue_handler); static irqreturn_t read_interrupt(int irq, void *dev_id) { if (gpio_get_value(TOUCH_IRQ_PIN)) schedule_work(&mywork); return IRQ_HANDLED; } void my_workqueue_handler(void *arg) { //do interrupt work here }

I'll read through the documentation you provided and post an update.

I had some time to look into this tonight. "enable_irq_wake(TOUCH_IRQ_PIN);" did the trick.

To hook it in with /sys/devices/.../wakeup, device_may_wakeup can be used.

Thanks for the references.